.content4 .cen{
	width: 91%;
	margin: 30px auto;
}
.content4 ul{
	list-style: none;
	margin-top: 50px;
	width: 100%;
}
.content4 li{
	float: left;
	width: 275px;
    height: 275px;
    display: inline-block;
    position: relative;
    font-size: 14px;
    line-height: 24px;
}
.content4 .long-pic{
	width: 550px;
	margin-bottom: 30px;
}
.p-wrap{
   display: none;
}
.p-img{
    width: 224px;
    height: 160px;
	line-height: 35px;
	margin: 30px auto;
}
.p-wrap{
    position: absolute;
	top:0;
	margin: 0;
	color:#fff;
	width: 100%;
	height: 100%;
	background: rgba(0,0,0,0.3);
}